Various devices have a limited energy supply, such as those that are powered by batteries. Some devices exist which may respond to voice commands or other occasional predetermined sounds (generally referred to herein as audio of interest). In general, devices may process an audio signal to detect any audio of interest. Most of the time, however, there is no audio of interest present in the audio signal. Furthermore, processing of the audio signal may cause the device to consume current, thereby increasing a power consumption in the device. The audio signal processing, thus, may limit a battery lifetime (notably a stand-by time) of the device.